A. Field of the Invention
The present invention relates generally to air filtration systems, and more particularly to a filtration system for use in a rotary broom sweeper having a horizontally mounted cylindrical segmented bore filter that is directly insertable through the top of the hopper of the rotary broom sweeper.
B. Description of the Prior Art
In the art of power sweepers and similar types of equipment, various attempts have been made to develop air filters for removing the dust entrained in the sweeper vacuum air flow. Conventional power sweepers are typically provided with a hopper, which may include a vacuum or suction air flow system including a filter which is periodically cleaned by vibrating the filter element or by removing and replacing the filter element. There are several disadvantages associated with the prior art type power sweeper filters and an important aspect of the filter system requires that the filter be very compact, be capable of sustaining high loadings of particulate material entrained in the sweeper suction air stream and be capable of automatic or selective cleaning operations without removing the filter from the hopper.
In U.S. patent application Ser. No. 680,942, filed Dec. 12, 1984, there is disclosed a sophisticated self-cleaning filter system for use in sweepers adapted for severe environments. The system of application Ser. No. 680,942 includes a single vertically oriented segmented bore oval filter. The oval filter provides substantial filter surface with a minimum vertical height. Among other desirable features, that system provides ideal vertical positioning of filter media pleating to enhance reverse flushing of the dust cake and provides adequate media surface in a single filter that is easily accessed for replacement.
The oval filter, however, is rather uncommon in pleated media filters. The most common filter form in industry is of a cylindrical open bore with one end of the bore closed by an endcap and having a mounting drawbolt hole located on the center axis of the cylinder for the purpose of mounting the filter within the cabinetry. A cylindrical filter having filter media area equal to an oval filter and mounted in its normal vertical position relative to pleat lay would have excessive length relative to hopper depth for use in a rotary broom sweeper. In other words, due to geometric constraints on the construction of the hopper, a vertically mounted pleated media filter with its associated self-cleaning apparatus would require a housing too tall to fit practically within the hopper of a rotary broom sweeper.
Accordingly, it is an object of the present invention to provide a filter system that overcomes the shortcomings of the prior art. More particularly, it is an object of the present invention to provide a self-cleaning filtration system for a mobile rotary broom sweeper utilizing a single cylindrical filter mounted in a horizontal position wherein the filter is inserted into the hopper in a direction perpendicular to the axis of the filter element, as for example through the top of the mobile rotary broom sweeper hopper.
It is a further object of the present invention to provide a self-cleaning filtration system for a mobile rotary broom sweeper which includes a single horizontally mounted filter element within the debris hopper in which the filter element is inserted through the normal hopper entry means into a cradle, which guides and supports the filter element during installation.
It is yet a further object of the present invention to provide a cylindrical pleated filter mounting system that provides for filter inserting in a direction perpendicular to the major axis of the filter, which may be either horizontal or vertical.
It is a further object of the present invention to provide a cylindrical pleated filter with a permanently segmented bore which permits a single filter to act as multiple filters for a filter mounting system as herein described.